Survival Results by the Prospectively Determined Clinical Staging for Locally Advanced Gastric Cancer: A Follow‐Up Study of JCOG1302A

ABSTRACT Background Long‐term overall survival (OS) of gastric cancer stratified by the prospectively determined clinical stage remains unclear. Methods This is an ancillary study of JCOG1302A, a prospective observational study that evaluated the accuracy of clinical diagnosis of gastric cancer with cT2/T3/T4, cN0/N1/N2/N3, and M0. The cT diagnosis was comprehensively determined by upper gastrointestinal endoscopy and upper abdominal contrast CT scan with 1 or 5 mm slice thickness. Lymph nodes with a minor axis greater than 8 mm or a major axis greater than 10 mm were defined as positive for metastasis. This follow‐up study evaluated OS in eligible patients from JCOG1302A. Results Among 1 260 patients enrolled in JCOG1302A between July 2013 and November 2014, survival data of 1 176 were analyzed. With a median follow‐up of 6.0 years for 821 surviving patients, the 5 year‐OS was 82.1% (95% CI, 77.3–85.9) in cT2 ( n = 319), 72.7% (68.2–76.6) in cT3 ( n = 450), 60.0% (54.9–64.7) in cT4a ( n = 401), and 40.0% (5.2–75.3) in cT4b ( n = 6), while that was 78.0% (74.2–81.2) in cN0 ( n = 559), 70.6% (65.4–75.2) in cN1 ( n = 350), 59.1% (52.5–65.1) in cN2 ( n = 241), and 28.4% (12.7–46.5) in cN3 ( n = 26). When combined with cT and cN, 5y‐OS was 83.5% (77.8–87.8) in cT2N0 ( n = 226), 77.2% (71.0–82.2) in cT3N0 ( n = 232), 66.8% (56.3–75.2) in cT4aN0 ( n = 100), 78.7% (68.6–85.8) in cT2N(+) ( n = 93), 68.0% (61.1–73.8) in cT3N(+) ( n = 218), and 57.7% (51.7–63.2) in cT4aN(+) ( n = 301). Conclusion Clinical T and N categories were associated with OS in locally advanced gastric cancer, providing prognostic information that may help identify higher‐risk clinical subgroups.